IT WAS A WESTERN WINTER ON THE UTC by Jim Morgan
A single word best describes +he ornl+holdgical happenings on the UTC this past winter.. ..WESTERN! One has to go back some time to recall a more impressive list of
western rarities than we had on the UTC this winter. Well documented sightings
during the winter of 1979/1980 included Western Grebe, Black-chinned hummingbird,
an Incredible 20+ Anna's Hummingbirds, a highly probably Allen's Hummingbird, four
Ash-throated Flycatchers, Bewick's Wren, +wo Varied Thrushes, Yellow-headed Blackbird, +wo Wes+ern Tanagers, Hepatic Tanager, Lesser Goldfinch, an impressive four
Green-tailed Towhees, Lark Bunting, and who knows how many Clay-colored Sparrows.
And no more than a half-hour's drive west of the UTC, in little birded Colorado
Coun+y, +he Attwa+er Prairie Chicken NWR Christmas Count turned up six Say's Phoebes
Sage Thrasher, two Green-tailed Towhees, _[2 Lark Buntings, and 25 Clay-colored Sparrows!
The Impressive movement of western species Into the UTC was accompanied by an equall
impressive movement of Groove-billed Anis from the southwest, along with two Buff-
bellied Hummingbirds and a Tropical Kingbird. Twice during the winter I had 7 or
more Anis in binocular view at one time, once in north Baytown, the other time in
Galveston. The fact is, Anis were everywhere in good numbers.
In my opinion, two species really stood out this past winter....Anna's Hummingbirds
and Clay-colored Sparrows. These two species were present In numbers unprecedented
for +he UTC and one flirts wi+h words like "invasion" to describe their movement.
Kelly Bryan from Hun+sville +old me +ha+ Anna's Hummingbirds also were In his area
like never before, and I unders+and +ha+ several showed up in Louisiana. Why? And
those Clay-colored Sparrows! I personally lost count at 40 Individuals when I included both fall and winter sightings. I suspect that hundreds of this usually very
rare species were present on the UTC and in adjacent counties. Again, why?
When one searches for reasons why such above described phenomena occur he considers
such factors as weather, food supply, and even the more recent theory of habitat
destruction causing birds to move far beyond their normal boundaries. When the
SPOONBILL Editor asked me to do this article she was hoping I could find some of
the answers. Right now I can only speculate on the reasons involved for the unusual
movement of the western rarities into the UTC this past winter. In time, the seasonal reports in American Birds and o+her articles in the literature may provide the
answers or at least some clues.
So let's speculate a little. The weather this past fall and winter has been relatively mild nationwide (compared particularly with the recent much harsher fall/
winter seasons). And would weather start a Clay-colored Sparrow movement of mass
proportions which was evident on the UTC as early as mid-October? Probably not. If
weather was any factor at all it may have accounted for holding the hummingbirds on
the UTC, since shrimp plant and other vegetaion has been spared through much of this
past mild winter. But what brought all the Anna's Hummingbirds here in the first
Habitat destruction surely Is a disruptive and stress causing factor as far as birds
are concerned, and no doubt some range changes, distribution pattern changes, and
even vagrancy results from this factor. But It Is hard to imagine Anna's Hummingbird and Clay-colored Sparrow "invasions" to be the result of habitat destruction
over a one year (or shorter) period.
The most logical reason for the western species to move into our area (and surrounding areas) this past winter is the lack of an adequate food supply in their normal
wintering range. What really makes this past winter puzzling Is fhat the makeup of
species involved in this movement included seed eaters as well as species relying
mainly on insects for food. It is hard to imagine a positive correlation between
Anna's Hummingbird and Clay-colored Sparrow movements, and one could argue that it
was just a coincidence. As for the multitude of other western rarities on the UTC,
could it be that we now have more observers who have just witnessed and reported a
phenomenon that occurs much more often than any of us suspected?
Perhaps some of our SPOONBILL readers who live outside the UTC can provide us with
some clues to what happened on the UTC this past winter. It would be very interesting to find out if Clay-colored Sparrows occurred in west and central Texas in fewer
or greater numbers this winter....or were their numbers normal? Similarly, were
Anna's Hummingbirds in anything hut normal numbers out west?
It has been interesting and fun to witness a "western11 winter on the UTC. It would
now be just as Interesting to know why we had the western birds to observe.